Tissue Injury and Repair. Flashcards
What happens to a muscle when tensed and resting?
When a call is active (tensed) it exhibits hypotrophy.
When a cell is inactive (resting) it exhibits atrophy.
What are the causes of cellular injury. (6)
ATP depletion Mitochondrial damage. Increased intracellular calcium Oxidative stress Membrane damage DNA and protein damage.
What is tissue regeneration?
Complete reconstruction of tissues with high proliferative capacity.
Viable stem cells and intact connective tissues is required.
What is tissue repair?
A combination of regeneration and scar formation.
Rate of repair depends on capacity to regenerate, extent of injury and extent of fibrosis.
List some examples of tissue injury (fibrosis)
Chronic inflammatory disease- chronic pancreatitis.
List some examples of tissue injury repair.
Deep wounds
MI
List some examples of tissue injury regeneration.
Liver regeneration after partial hepatectomy.
Superficial skin wounds.
Reabsorption of exudate in pneumonia
Nephrons following nephrectomy
Explain the sequences of heeling
Inflammation Angiogenesis Migration Scar formation Connective tissue remodelling
Explain the stages of normal cutaneous wound healing.
Following trauma homeostasis, inflammation and cell migration occurs. This takes 0-3 days.
The next stage is cell proliferation. Takes 3-7 days.
Final stage involves remodelling, wound closure and contraction. This takes 10-14 days.
What local factors affect wound healing?
Size of wound.
Location (how vascularised)
Type of wound
Infections, mechanical forces, foreign bodies.
What systemic factors affect wound healing?
Nutritional status.
Metabolic status- Diabetes
Circulatory status
Hormones- glucocorticoids.
List some complications of repair.
Deficient scar formation.
Excessive repair- granulation tissue, excessive collagen accumulation- hypertropic scar), keloid.
Formation of contractures (burns)
